1. Field of the Invention
This invention relates in general to information systems and more specifically to a free-space optical system in an information system.
2. Description of the Related Art
Information systems such as computer systems, cellular phones, wireless devices, PDA's, and electronic control systems for automobiles utilize multiple integrated circuit chips for performing functions of the system. These integrated circuit chips are communicatively coupled via wired busses e.g. wires or circuit traces for exchanging information.
Recently, systems have been proposed where information may be exchanged between devices of an information system with optical communication for increasing bandwidth and speed. One solution is to use wave guides for carrying the optical signals between chips. One example is the use of wave guides to exchange information between a processor and a memory.
One problem with the use of a waveguide is that it may be difficult to align components to a wave guide on a circuit board. Another problem is that the waveguides themselves add expense to the system.
Information may be transferred optically where at least some portion of the optical link passes through free-space (i.e. not through a wave guide). These systems may be referred to free-space optical systems in that at least some portion of the link passes through free-space. An optical link passing through “free-space” includes not only an optical link passing through atmospheric air, but also includes an optical link passing through any gas, vacuum, or liquid where the container of such medium does not act as a waveguide.
One problem with a free-space optical system is that the components of the link must be aligned within certain tolerances to meet information transmission requirements. For example, the optical transmitter, deflector structures, and the optical receiver must be aligned to ensure a desired level of information transmission.
Although care can be taken to ensure that the components are aligned when assembled, such systems may be subjected to vibration (e.g. dropping) or temperature variation during use. For example, components of an optical link may become misaligned if a cell phone or notebook computer is accidentally dropped on a surface. Furthermore, the cost for designing and assembling components that are precisely aligned may be cost prohibited.
What is needed is an improved system for a free-space optical communication system.
The use of the same reference symbols in different drawings indicates identical items unless otherwise noted. The Figures are not necessarily drawn to scale.